Light-sensitive para quinone diazides for making printing plates



United States Patent Ofiice 2,754,209 Patented July 10, 1956 LIGHT-SENSITIVE PARA QUINONE DIAZIDES FOR MAKING PRINTING PLATES Maximilian Paul Schmidt and Oskar Siis, Wiesbaden- Biebrich, German assignors, by mesne assignments, to Azoplate Corporation, Summit, N. J., a corporation of New Jersey No Drawing. Application June 10, 1952, Serial No. 292,749

Claims. (Cl. 95-7) The present invention relates to the field of photomechanicalreproduction. More particularly it affords a new light-sensitive material suited for the photomechanical duplication of images. The reproduced images may be used directly as printing plates.

The method of photomechanically producing so-called tanned images in a layer consisting of a Water-insoluble colloid that may be hardened by the products produced by the action of light upon certain light-sensitive sub stances incorporated in the colloid is well known. Formerly, salts of chromic acid were principally used as the light-sensitive substances in such processes. More recently, water-soluble aromatic diazo compounds have also been employed for this purpose. In view of the fact that colloids hardened by the action of light are capable of retaining greasy ink, the above methods have been used for the photomechanical production of printing plates for use in the graphic industry. Printing images that are negative with respect to the master pattern are obtained by these methods. Further treatment is necessary to transform such printing images into images that are positive with respect to the master pattern.

Still more recently, it was found that the products formed by the action of light upon certain water-soluble aromatic diazo compounds were in themselves capable of retaining greasy ink and materials free of colloids suitable for producing both negative and positive images have been produced. This colloid-free light-sensitive material is an improvement compared to material containing colloids because of its simple structure. However, like the older materials, it has a limited shelf life or storage stability before use.

The object of this invention is a new light-sensitive material sensitized by a layer containing as a light-sensitive substance a p-quinone diazide (quinone-(l,4)-diazidc) that is difiicultly soluble in water (i. e. hard to dissolve in water or insoluble in water) but which can be dissolved in organic solvents. Especially well suited are water-insoluble p-quinone diazides of the benzene or naphthalene series and containing at least one esterified or amidated sulfo-acid-group or carboxyl group.

The quinone-(1,4)-diazides used in accordance with this invention are characterized by the fact that they can be dissolved in organic solvents but are insoluble or hard to dissolve in water. They are applied in the form of solutions in organic solvents that uniformly wet the surface of the base material; preferably in solvents whose boiling points are within the temperature range of 70 to 120 C. These solutions are used to form a thin uniform layer by whirlcoating, brushing, or spraying. Due to the excellent stability of the p-quinone diazides, it is possible to remove the solvents from the layers completely by heating the coated support to higher temperatures. A firm attachment of the film-like layer to the base material is thus achieved.

The formation of a film on the base material frequently is facilitated by adding to the sensitizing solutions substances which tend to prevent crystallization, preferably alkali-soluble resins, such as alkali-soluble phenol-formaldehyde resins. The quantity of such crystallizationpreventing additions may be between approximately 5 and 50% calculated on the light-sensitive substance present in the solution. Such additions also actually improve the afiinity of the sensitizing solutions to the surface of the base material, especially to metals, and thus increase the adhesion of the light-sensitive layer to the base.

It may prove of advantage to use a mixture of several quinone-(1,4)-diazides in order to preclude any crystallization of the layers. This method is recommended, for instance, in the case of naphthoquinone-(l,4)-diazides of lower molecular weight, e. g. in the case of substituted and non-substituted naphthoquinone-(1,4)-diazide-(4)- sulfo-acid esters and naphthoquin0ne-(l,4)-d.iazide-(4) sulfo-acid amides. These substances show a stronger tendency to crystallize.

The addition of a resin to the light-sensitive layer frequently proves of advantage for the purpose of preventing the light-sensitive substance from crystallizing or in case it is intended to etch the images on metallic bases. For the purpose of rendering the images better visible, e. g; when producing stereotypes, dyes can be added to the layers.

Metals, like zinc and especially aluminum, are excellently suited to serve as base material. It is not necessary to subject the metals to be used to any special preliminary treatment of a chemical nature in order to render their surfaces suitable for accepting the light-sensitive layer. A simple mechanical roughening of the metallic surface proves quite suificient for the application of the lightsensitive layer which firmly attaches itself to the metallic base in the form of a thin uniform film. Other base materials used in photomechanical reproduction processes for the production of printing plates can also be employed, e. g. plates of stone or glass and, also sheets of paper, the latter possibly requiring some special treatment.

The coated light-sensitive material is exposed to a light image. It is recommended to accomplish this by exposing the light-sensitive material to light through a transparent pattern. However, it is also possible to expose it to a projected image. The exposure will tend to bleach the light-sensitive layer so that the image will become visible. The contrast between the exposed and unexposed areas will largely depend on the original color of the light-sensitive layer. In developing an image for use as a printing plate for instance, use is made of the differences between the exposed and unexposed diazo compound with respect to solubility in a solvent, which may be an organic solvent, dilute acid, dilute alkali or a combination of solvents. The light-transformation products, as a rule, are harder to dissolve in the above-mentioned agents.

The image is developed, for example, by wiping the material, subsequent to its exposure, with a solvent, which may include water or dilute acids or acid salts. There remains, for example, on a clear metallic background, a. negative image that readily accepts and retains greasy ink.

The application of organic solvents is especially recommended in the case of quinone-(l,4)-diazides of the benzene and naphthalene series, which contain esterified or amidated carboxyl groups. The development is effected advantageously with dilute alkalies in the case of quinonc-(l,4)-diazides with amidated sulfo-acid-groups, in particular in such cases where a hydrogen atom at the nitrogen atom of the sulfonamide residue remains unsubstituted. It is expedient to bathe the exposed material in the developing solution to bring out the image, which can then be used for printing subsequent to a brief aftertreatment with dilute acid.

by a subsequent treatment withalkaliesi In some cases the light-sensitive layers produced with quinone-(l,4)-diazides can also be used successfully for the positive working process, such use depending partly on their constitution and partly on the method of developing the copies. 7

While,,in the case of the quinone-(1,4)-diazides of the benzene series, negative images, as a rule, are obtained from positive patterns, it is possible also to produce, for instance with the quinone-(l,4)-diazides of the naphthalene series, positive images from positive originals, since the light-decomposition product may under certain cir-' cumstances be more readily soluble, for example in dilute alkalies, than the diazo compound still present as an oleophilic product at the portions of the layer not affected by light. V In case the naphthoquinone-(l,4)-diazides contain merely one sulfo-acid amide orcarboxylic-acid amide residue, they are better suited for the negative working processthan for the positive working process. It is best to develop the images in the'presence of an organic solvent, e. g. alcohol. Aqueous alcohol, with the pos" sible addition of soluble salts, like calcium chloride with or without ,tri-ethanolamine, has proven very well suited for this purpose.

' In case the naphthoqu1none-(1,4)-diazides contain several sulfo-acid ester residues or several sulfonamide residues, they are, as a rule, suited also for the positive working process, since the copies in this case can be developed with alkaline solutions Without the addition of solvents.

In case the naphthoquinone-(l,4)-diazides contain a basic residue, e. g. an imidazole ring, that renders the diazo compounds slightly basic, such compounds are excellently suited for the negative working process since the layers produced with them can be developed with dilute acids, to which solvents or water-soluble colloids may be added in certain cases.

The layers produced with the quinone-(l,4)-diazides that are to be used in accordance with this invention in most cases have only a pale color. The same is true of the light-decomposition products of these diazo compounds. In order to make it easier to follow the development of the copy up to the finished image, it is recommended, therefore, to incorporate in the light-sensitive layer certain substances that will yield coloured compounds under the action of light. Well suited for this purpose are orthoquinonediazides (quinone-(l,2)-diazides), in particular such diazides belonging to the benzene series. They, tend to yield, when exposed'to light, socalled irradiation dyes (compare Liebigs Annalen der Chemie, volume 556 (1944), pages 65-84). (It is possible also to add dyes to the layer, since when the image is developed, they remain with the image elements on the surface of the layer base, while they are removed at the water-bearing non-printing areas. s

As already pointed out, the. sulfo-acid esters and the carboxylic-acid esters, also the sulfonamides and the carboxylic-acid amides of the water-insoluble naphthoquinone-(l,4)-diazides are especially well suited, due to their excellent stability, for the production of light-sensitive layers.

The diazo compounds to be used in accordance with this invention are suitably produced, for instance, by the diazotization of the respective sulfonic-acid amides and carboxylic-acid amides of the 1-hydroxy-4-amino-benzenes and the p-amino-naphthol's. It is a noteworthy fact, in this connection, that, even in a mineral-acid medium, the quinone-(l,4)-diazides are formed directly in most cases,

7 whereas otherwise, as is the case with the non-substituted 4-amino-1-hydroxybenzene e. g. (compare Hantzsch, Berichte der Deutschen Chemischen Gesellschaft 29, (1896) page 1528), primarily the diazonium salts are formed which must be transformed into their anhydrides The p-amino-phenols from which the diazo compounds: are manufactured, may be prepared as follows:

(1) o-hydroxy-carboxylic acids are condensed with bases or phenols in the presence of agents that attract. Water. A nitro or nitroso group is introduced, into the: p-position relative to the hydroxyl group of the carboxylic-acid amides or esters thus obtained, by treatment with nitric acid or nitrous acid. The reaction products are; converted by reduction into p-amino phenols in the customary manner.

(2) 1-chloro-4-nitro-benzene-Z-carboxylic acids are condensed with bases or phenols in the presence of agentsthat attract water, and, bymelting the amides or esters thus obtained together with alkali acetate in the presence of acetamide, the chlorine is replaced by hydroxyl. The hydroxy nitro-carboxylic-acid amides or esters are con-- verted into quinone diazides as indicated under (1).

(3) The l-chloro-4-nitrobenzene-Z-sulfochlorides or their substitution products are condensed with bases or phenols, and, either by boiling the condensation products for some time with aqueous alkalies or by melting them together with a mixture of potassium acetate and acetamide, the chlorine atom is replaced by a hydroxyl group. The hydroxy-nitrobenzene-sulfochlorides are reduced and subsequent to the reduction, the hydroxy-amino compounds thus ob tained'are converted into quinone diazides in known manner.

(4) The sulfo acids of p-quinone diazides are converted, by treating them with chlorosulfonic acid, into sulfochlorides, and the latter compounds are caused to react with phenols or amines.

The naphthoquinone-(l,4)diazide-4-sulfo esters and naphthoquinone-(1,4)-diazide-4-sulfonamides are obtained, for instance, by causing the respective sulfochlorides to react with aromatic hydroxy compounds and aromatic amino compounds or with aromatic hydroxy-arninocompounds, Whereas the carboxylic-acid esters and amides of the naphthoquinone-(l,4)-diazides can be prepared by using as parent-materials naphtholcarboxylic-acid esters or amides, which are converted in the customary manner into p-nitroso compounds or the p-azo dyes. These reaction products are then subjected to reduction. The pamino naphthol derivatives thus obtained are finally diazotized. V

The following formulae which are referred to in the subsequent examples represent compounds which may be used according to the present invention; it is not intended to limit the scope of the invention to the formulae disclosed or to the subject matter described in the examples. I i

jsorNHotH n c p gsm-nn-m 1, j p, r p is V 3) o s i i 0 u s M 7 u SO NHNH-SO2 n I N: N:

Sm-000m n I n Or-NHOOHr-ONH-S 02- iv: (26) can enus ll u N so,o

g) N- C-CgH5 S0aO- I? H N: (27) o H3C T -=1TT @SW-N-O ll N:

SO:NH-(CH2)r-CH3(1L) ll N2 SOr-N V N I CH;

Examples (1) 0.2 gram of the diazo compound conforming to the Formula 1 are dissolved in 10 cc. of glycol-monomethyl ether, and this solution is used to coat a mechanically roughened aluminum foil by means of a centrifugal disc. The layer is thoroughly dried by means of a hot air current and by subsequently placing it for five minutes in a drying cabinet at a temperature of 90 C. The sensitized material is exposed under a transparent pattern, to the radiation of an arc lamp of718 amperes for one to two minutes at a distance of 70 cm. The image is developed by Wiping over the exposed foil with a cotton swab soaked with water and subsequently treated with a one-percent solution of phosphoric'acid. A negative image is obtained from a positive master Which takes greasy ink and can be used as a printing plate.

'In order to prepare the diazo compound conforming to the Formula 1, one mole of 1-chloro-4-nitrobenzene-2- sulfochloride (Berichte der Deutschen Chemischen Gesellschaf 24, (1891) page 3196) is caused to react with two moles of aniline in a solution of 'dioxane at normal temperature. The l-chloro-4-nitrobenzene-2-sulfo-anilide thus obtained melts when recrystallized from alcohol, at a temperature of from 167 to 169 C. By heating the sulfo-anilide for three hours with an approximately 22- percent solution of caustic potash, l-hydroxyl-nitrobenzene-2-sulfo-anilide (melting point of 161-163 C.) is formed. This product is reduced catalytically with a Raney-nickel contact catalyst in an alcoholic solution to 7 form 1-hydroxy-4-aminobenzene-2-sulfo-anili e. After the alcohol has been removed from the reduction liquid by vaporization, the remaining l-hydroxyl-aminobenzene-2-sulfo-anilide, a sirup-like product, is diazotized with a solution of sodium nitrite in a solution of hydrochloric acid. The benzoquinone-(1,4)-diazide-(4)-2- sulfo-anilide separates in the form of fine, pale yellow crystals and melts at 160 C. under decomposition.

It may be useful to wipe over the printing plate, especially if it is not used directly, with an aqueous solution to be applied in the printing technique and which contains 8% dextrine, 1% phosphoric acid and 1% formaldehyde; thereafter the printing plate is dried.

(2) An aluminum foil, which has been pretreated as described in Example 1, is coated with alight-sensitive solution of 0.1 gram of the diazo compound conforming to the Formula 2 and 0.02 gram of a formaldehyde-phenolresin-novolak, which is sold by the firm Chemische Werke Albert at Wiesbaden-Biebrich under the trade-name Alnovol (registered trademark in Germany), in'lO cc. of glycolmonomethyl ether. It is then predried with hot air and subsequently redried for about ten minutes in a drying chamber at a temperature of 96 C. The light sensitive foil is exposed to light under a negative transparent screen pattern, is bathed for approximately ten to twenty seconds in a 0.4-percent solution of trisodium phosphate, and rinsed with water. Then the image side is briefly wiped over with a one-percent solution of phosphoric acid. The foil thus developed and subsequently inked with greasy ink constitutes a positive printing plate.

The diazo compound conforming to the Formula 2 is prepared in accordance with the procedure described in Example 1. Equimolecular quantities of 1-chloro-4- nitro-benzene-2-sulfochloride and B-naphthylarnine are condensed in the presence of pyridine. The l-chloro- 4-nitrobenzene-2-(N-fi-naphthyl)- sulfonarnide (melting point, 168-169 C.) thus obtained is converted, by boiling for about twenty hours together with an approximately twenty-percent solution of caustic potash, into thedi-potassium compound of 1-hydroxy-4-nitrobenzene- Z-(N-B-naphthyl)-sulfonamide. This precipitates from the alkaline solution in the form of yellow prismatic crystals during the heating period. It is catalytically reduced in an aqueous solution by means of Raney-nickel. The 1 hydroxy 4 amino benzene 2 (N 8 naphthyl)-sulfonamide is diazotized with sodium nitrite in a solution of hydrochloric acid. The slightly yellow-colored benzoquinone (1,4) diazide (4) L 2 (N B- naphthyl)-sulfonamide is decomposed at a temperature exceeding 155 C. when heated in a capillary tube.

(3) An aluminum foil is coated with a two-percent solution of the diazo compound conforming to the Formula 3 in glycol-monomethyl ether. The thoroughly dried foil is subsequently exposed behind a negative transparent pattern to the radiation of an arc lamp for about 1.5 minutes. The exposed foil is developed by wiping with a cotton swab soaked in an one-percent solution of phosphoric acid, and the image is inked with greasy ink. A positive image, which can be used for printing, is obtained from a negative pattern.

The diazo compound conforming to the Formula 3 is obtained by condensing one mole of p-phenylene-diamine with 2.2 moles of 1-chloro-4-nitrobenzene-2-sulfoch1oride in dioxane with the addition of pyridine. The N,Nf di (1 chloro 4 nitrobenzene 2 sulfonyl)- p-phenylene-diamine is converted with a boiling solution of caustic potash (approximately 22 percent) into N,N'- di (1 hydroxy 4 nitrobenzene 2 sulfonyl) pphenylene-diamine, which is catalytically reduced in alcoholby means of Raney-nickel to form N,N'-di-(1-hydroxy 4 amino benzene 2 sulfonyl) p phenylenediamine. The diazotization of the base is effected by adding to the slightly alkaline solution of the base the necessary amount of sodium nitrite and acidifying this solution with acetic acid. The N,N' di [benzoquinone (1,4) diazide (4) 2 sulfonyl] p phenylenediamine forms a fine-grained, brownish-yellow-colored precipitate and gradually decomposes when heated in a capillary tube to a temperature exceeding 200 C.

(4) A roughened aluminum foil is coated witha solution consisting of 0.2 gram of the diazo compound conforming to the Formula 4, 0.1 gram of Alnovol (compare Example 2), and ten cc. of glycol-monomethyl ether. The light-sensitive foil is exposed to light under a transparent pattern and is developedby first applying a ten-percent solution of trisodium phosphate and subsequently treating it with dilute phosphoric acid. An image, negative with respect to the pattern used, is obtained, which can be employed for printing after being inked with greasy ink.

Thediazo compound conforming to the Formula 4 is obtained by the catalytic reduction of 1-hydroxy-4-nitro- 2-benzoic-acid anilide (compare Liebigs Annalen der Chemie, volume 210 (1881), pages 342-343) by means of Raney-nickel in an alcoholic solution. The l-hydroxy 4 amino 2 benzoic acid anilide (meltingpoint after recrystallization from alcohol, 174175 C.) is diazotized in glacial acetic acid with a2 n-sodium nitrite solution. On carefully adding water to the diazotization solution, the benzoquinone-(1,4)-diazide- (4)-2-benzoic-acid anilide precipitates in the. form of small glittering, yellowish-brown crystals thatv decompose at approximately 140 C.

(5) 0.2 gram of the diazo compound conforming tothe Formula 5 is dissolved in cc. of dioxane and this solution is usedfor coating a mechanically roughened aluminum foil. After the layer has been thoroughly dried, the sensitized foil is exposed to light underapattern as explained in Example 1, and theimage thus produced is subsequently developed by being wiped over first with water and then with a one-percent solution of phosphoric acid. The practically colorless image, which is negative with respect to the master, appears clear-and sharp when inked with greasy ink, and can bereproduced on paper by means of one of the customaryprinting machines. It is possible to produce arlarge'number of copies.

The diazo compound conforming to they Formula5 is prepared by condensing equimolecular quantities of salicylic acid with N-ethylaniline, in boiling toluene in the presence of phosphorus trichloride, to form salicylicacid-N-ethyl-anilide (after recrystallization from aqueous alcohol it has a melting point of 78 8 1 C.). The

nitration of the anilide with 1.2 mol of concentrated nitric acid in glacial acetic acid at room temperature yields hydroxy 4 nitro 2 benzoic acid N,- ethyl: anilide. This product accrues in the form of abrown oil and becomes crystalline only after standing for a longer period or" time (melting point, 55 66 C.). The nitro compound is reduced, analogously to the procedure 10 indicated in Example 6, to form 1 hydroxy 4 aminobenzene- 2 benzoic acid N ethyl anilid'e, which is diazotized in the customary manner.

(6) A two-percent solution of the diazo compound conforming to the Formula 6 in a mixture consisting of equal parts of methyl-ethyl ketone and of dioxane is applied by whirlcoating to an anodically oxidized alu, minum foil. The dried foil is exposed to light behind a transparent pattern and the image obtained, which is negative with respect to the pattern used, is developed with an one-percent solution of phosphoric acid. Subsequent to being inked with greasy ink, the image can be used as a printing form;

In order to produce the diazo compound conforming to the Formula 6, salicylic acid is caused to react, analogously to the method indicated in Example 7, with 2,5 dimethyl aniline. The salicylic acid 2,5 dimethyl-anilide melts at atemperature of 157-161 C. The nitration of the anilide in glacial acetic acid yields 1 hydroxy 4 nitro 2 benzoic acid 2',5 dimethyl anilide (melting point: 167169. C.), which is catalytically reduced to form 1 hydroxy 4 amino 2- benzoic acid 2',5' dimethyl anilide. The latter is purified as the hydrochloride by recrystallization from The benzoquinone (1,4)- diazide (4) 2 benzoic acid 2',5' dimethyl ani-- lide precipitates in the form of an intensely yellow col-- ored sediment which decomposes at 122 C.

(7) A solution of 0.1 gram of the diazo compound. conforming to'the Formula 7 in 10 cc. of glycol-monomethyl ether is brushed aluminum foil. The layer is dried with the aid of a current of hot air (approximately C.). The light. sensitive foil is exposedto light, as indicated in Examplev 1, under a transparent'paper pattern, and the image pro-- duced is developed with a solution prepared from 70 cc.. of ethyl alcohol, 10 cc. of a twenty-percent solution of phosphoric acid, and'80 cc. of water. The image thus obtained, which is negative with respect to the pattern, can be inked-immediately with greasy ink and can then be used as a printing plate.

in order to produce the diazo compound conforming to the Formula 7, 1-chloro-4-nitrobenzene-Z-carboxylic acid is condensed with fl-naphthylanline in the presence of phosphorus trichloride, to form 1-chloro-4-nitrobenzoic-acid-naphthyl amide (melting point, 191 C.). The condensation product is heated at a temperature of 170-175 C. together with an equal quantity of anhydrous sodium acetate and a four-fold quantity of acetamide. Then the melted mass is digested with approximately double the amount of water, and the resulting residue is dissolved, while heat is applied, by means of a sixteen-percent solution of caustic soda. By the acidification of the solution with dilute sulfuric acid, the resulting l-hydroxy-4-nitro-benzoic-acid-naphthyl amide (melting point: 238-239 C.) is separated. It is then catalytically reduced in the presence of nickel, and the amino compound thus obtained is converted in known manner, subsequent to its purification as hydrochloride, into benzoquinone (1,4) diazide (4) 2 benzoic acid 5 naphthyl amide. This diazo compound begins getting black at a temperature of C. and slowly chars when heated for a longer period of time.

(8) 0.2 gram of the diazo compound conforming to Formula 8 and 0.1 gram of Alnovol (compare Example 2) are dissolved in 10 cc. of glycol-monomethyl other at a temperature of approximately 50 C. This solution is brushedonto a superficially roughened aluminum foil. The sensitized foil is exposed to light under a transparent pattern, and the slightly yellow colored image thus produced, which is negative with respect to the pattern employed, is treated with a developer prepared from 80 cc. ofethyl alcohol and 20 cc. of a twenty-percent solution of phosphoric acid. Subsequent to being rinsed with on a superficially roughened:

ture of three parts of 11 a a water, the imageis'inked with greasy ink and can then be used as'a printing plate. t

The diazo compound conforming to the Formula 8 is produced, analogously to the method of preparation described in Example 8, from 3-methyl-2-hydroxy-l-benzoic acid and ,B-naphthylamine. The 3-methyl-2-hydroxy-lbenzoic-acid-fi-naphthyl amide melts at 1825-183 (1., while 5-nitro-3-methyl-2-hydroxy-l-benzoic-acid-B-naphthyl amide melts at 22923() C. The 5-amino-3methyl- Z-hydroxy-1-benzoic-acid-B-naphthyl-amide prepared from the before-mentioned nitro compound is diazotized in water-dioxane in a solution of hydrochloric acid. The 6 methyl benzoquinone (1,4) diazide (4) 2 benzoic-acid-B-naphthyl-amide melts at 145 C. under decomposition (fine yellow needles).

.(9) 0.1 gram of the diazo compound conforming to the Formula 9 is dissolved at a temperature of d-5G a.

in a mixture of cc. of glycol-monomethyi ether and 1 cc. of pyridine, and the cooled solution is applied in the customary manner to an aluminum foil. The lighsensitive layer is dried, and the foil is then exposed to light under a master pattern in the customary manner. The image thus produced is developed by being treated first with a fifteen-percent solution of disodium phosphate and subsequently with a one-percent solution of phosphoric acid. It is then rinsed with water and inked with greasy ink, and can be used as a printing plate for reproduction work.

in order to produce this diazo compound, two moles of salicylic acid are caused to react with one mole of p-phenylene-diamine in boiling toluene with the addition of one mole of phosphorus trichloride. The resulting N,N -di- 2-hydroxyl-benzoyl) -p-phenylene-diamine (Inciting point: 307308 C. under decomposition) dissolved in concentrated sulfuric acid, upon addition of the necessary quantity of potassium nitrate at room tempera ture turns into the N,N-di-(S-nitroQ-hydroxy-l-benzoyl)- p-phenylene-diamine, which after first darkening, melts at a temperature of approximately 28-3" C. under decomposition. Prom this compound there is formed by catalytical reduction. the N,N-di-(5-amino-2-hydroxy-1-benzoyl)-p henylene-diamine, which is converted into the diazo compound by the customary method.

(10) To an anodically oxidized aluminum foil, a solution prepared from 6.2 gram of the diazo compound conforming to the Formula 1t) and 10 cc. of a mixture consisting of equal parts of dioxane and of glycol-monomethyl ether is applied. The layer is thoroughly dried. The negative image produced by the exposure of the foil under a transparent pattern is developed by treating with a onepercent solution of phosphoric acid and is then inked with greasy ink.

The above-mentioned diazo compound is prepared by reducing the 5-nitro-salicylic-acid-phenyl ester (Fournal fiir praktisc'ne Chemie, volume 43 (1891), page 379) to form 5-amino-salicylic-acid-phenyl ester, the hydrochloride of which is converted into the diazonium chloride by reaction with the calculated quantity of sodium nitrite. From the aqueous solution of the diazonium chloride there is separated, by the addition of ammonia Water while cooling with ice, the quinone-(l,4)- diazide(benzoquinone (1,4) diazide (4) 2 carboxylic-acidphenyl-ester) in the form of a canary-yellow powder. it melts at 120 C. under decomposition.

(11) A zinc plate, pretreated with potassium alum and acetic acid, is coated with a two-percent solution of the diazo compound conforming to the Formula 11 in a mixglycol-monomethyl ether and two parts of methyl-ethyl ketone. The light-sensitive foil is exposcdunder a pattern for one to 1 /2 minutes to the radiation of an arc lamp of 18 amperes at a distance of 70 cm. The image produced is treated with a developer consisting of ten parts of a five-percent solution of acidsalts,rsimilar to that described, for instance, by Strecker in the German'Patent No. 642,7 82, and one part of ethyl alcohol. The developed image is a negative one with respect to the pattern employed. it can be inkedwith greasy ink and'can then serve as a printing plate.

The diazo compound conforming to the Formula 11 is prepared from S-nitro-salicylic-acid-fl-naphthyl ester Berichte der deutschen Chemischen Gesellschaft 26 (1893), page 1465, analogously to the phenyl ester mentioned in Example 12, by its reduction and subsequent diazotization. The benzoquinone-( 1,4) -diazide (4) -2-carboxylic-acid-B- naphthyl ester starts to sinterat a temperature of C. and melts at about C.

(12) A glycol-monomethyl ether solution is prepared, which contains two percent of the diazo compound conforming to the Formula 12 and, in addition, 0.2 percent of the dye designated as Eosin S (compare Schultz, Farbstoiftabellen, 7th edition, volume 1, page 375, No. 883). This solution is used to coat an aluminum foil as described in Example 1. The exposed foil is treated with a cotton swab saturated with a 0.2 percent solution of trisodium phosphate and thus an image is developed that is negative with respect to the pattern employed. The yellowish-red colored image is wiped over with a onepercent solution of phosphoric acid and is then used, subsequent to being inked with greasy ink, as a printing plate. V

The diazo compound conforming to the Formula 12 is prepared, by the method indicated in Example 1, from 1-chloro-4-nitrobenzene-2-sulfochloride and 2,4-dichloroaniline. The benzoquinone-(l,4)diafide-(4)-2-(N-dichloro-phenyl)-sulfonamide melts at 161 C. under decomposition.

(13) 0.2 gram of the diazo compound conforming to the Formula 13 is dissolved in 10 cc. of glycol-monomethyl ether. This solution is applied by brushing to the caseincoated side of a paper foil, which has been produced in accordance with the patent specification 'No. 2,5 34,5 88 and is coated on one side with a layer consisting of casein and clay; which layer has been hardened by means of formaldehyde. Subsequent to drying, the sensitized foil is exposed to they radiation of an arc lamp under a negative transparent pattern. The diazo compound that remained intact at the places of the light-sensitive layer not affected by light is removed by wiping over for approximately' one minute with a cotton swab soaked with a 6.3-

percent solution of trisodium phosphate, and then the surface of the foil bearing the image is wiped over with a one-percent solution of phosphoric acid. The positive image thus obtained can be inked with greasy ink and then be used as a paper printing plate for reproduction work in the customary printing machines.

By condensing 1-chloro-4-nitro-benzene-Z-sulfochloride with a-naphthylamine in an analogous manner to that described in Example 2, lchloro-4-nitrobenzene-2-(N-anaphthyl)-sulfonamide (melting point: 172 C.) is obtained. From this compound there is obtained, by hydrolysis with a solution of caustic potash, by catalytic reduction, and by diazotization, the benzoquinone-(1,4)-diazide- (4)-2-(N-a-naphthyl)-sulfonamide (Formula 13). This diazo compound is pale yellow. It darkens when heated and decomposes at a temperature of approximately 200 C.

(14) A paper foil of the is whirlcoated with a two-percent solution of the diazo compound conforming to the Formula 14 in glycolmonomethyl ether and the coated side is dried thoroughly. The foil is exposed to light under a transparent negative pattern and afterwards treated with a five-percent solution of disodium phosphate. The developed positive image is then fixed by wiping with a cotton swab soaked with a one-percent solution of phosphoric acid. Subsequent to being redried, the paper foil can be placed in one of the customary printing machines and after being wiped over with water, can be inked with greasy ink. it can then be used as a printing plate.

In order to prepare the diazo compound conforming to the Formula 14, thoroughly dried 2-chloro-bcnzo'quinone kind described in Example 13 I 13 (1,4)-diazide-(4)-5-sulfo acid is heated together with a fourfold to fivefold quantity by weight of chlor-sulfonic acid at a temperature of 110 CL 2-chloro-benzoquinone- (1,4)-diazide-(4)-5-sulfochloride is thus produced, which melts at a temperature of 171-172 C. under decomposition. From the sulfochloride there is obtained, by reaction with 2.2 moles of aniline in dioxane, 2-chlorobenzoquinone 1,4) diazide-(4) -5-(N-phenyl)-sulfonamide (fine yellowish-brown crystals that decompose at 170 C).

Parchmentized paper is coated with a solution prepared from 0.2 gram of the diazo compound conforming to the Formula 15, 5 cc. of dioxane and 5 cc. of glycolmonornethyl ether. After being thoroughly dried, the sensitized foil is exposed to light under a negative transparent pattern. The development of the positive image thus obtained is effected by wiping briefly with a 0.1- percent solution of trisodium phosphate and by subsequently wiping briefly with a cotton swab soaked with a one-percent solution of phosphoric acid. The image can be inked with greasy ink.

The diazo compound conforming to the Formula 15 is prepared by the bromination of benzoquinone-(1,4)- diazide-(4)-2-(N-phenyl)-sulfonamide (Formula 1) with one mol of bromine in glacial acetic acid. On addition of water the 6-bromo-benzoquinone-(1,4)-diazide-(4).-2-(N- phenyl)-sulfonamide separates from the glacial acetic acid solution in the form of brightly yellow-colored crystals, which decompose at a temperature of 160 C.

16) A paper foil of the kind described in Example 13 is whirlcoated with a solution of 0.2 gram of the diazo compound conforming to. the Formula 16 in 10 cc. of glycol-monomethyl ether. After being thoroughly dried, the light-sensitive foil is exposed to light under a negative transparent pattern, and the image thus obtained is devel oped by wiping for about thirty seconds with a cotton swab immersed in a ten-percent solution of disodium phosphate. Then the image is briefly wiped with a onepercent solution of phosphoric acid and subsequently is inked with greasy ink. A positive image on a pure white background is obtained, which can be used for printing.

In order to prepare the diazo compound conforming to the Formula 16, 1-chloro-4-nitrobenzene-Z-sulfonicacid-phenyl ester is heated together with 1.5 parts of anhydrous sodium acetate and 4 parts of acetamide for several hours at a temperature of 175 C. until a clear melt is obtained. The l-hydroxy-4 nitrobeuzene-Z-sulfonic-acid-phenyl-ester produced thereby is dissolved by the extractionof the reaction mixture with ether and, subsequent to the vaporization of' the ether, the resulting ester remains in the form of a brownish oil. This ester is catalytically reduced in an aqueous, slightly alkaline solution (nickel contact) and 1-hydroxy-4-amino-benzene-2-sulfonic-acid-phenyl ester is obtained. From this compound benzoquinone-(1,4)-diazide (4) 2 sulfonicacid-phenyl ester is prepared by diazotization in the form of fine bright yellow crystals that decompose at 148 C.

(17) A two-percent solution of'the diazo compound conforming to the Formula 17 in glycol-monomethyl ether is applied by brushing to parchmentized paper and is then dried thoroughly. The paper thus sensitized is exposed to light under a pattern and is developed, by means of a 0.5-percent solution of phosphoric acid, as a negative image that shows little color. When rubbed in with greasy ink, it appears in distinct outline.

The preparation of the diazo. compound conforming to the Formula 17 is eifected analogously to the method indicated in Example 2. 1-chloro-4-nitrobenzene-Z-sulfochloride is condensed with 4-amino-anisole and thereby is obtained 1 chloro 4 nitrobenzene 2 (N-4-methoxyphenyl)-sulfonamide (melting point after recrystallization from alcohol: 146C.), from which there is prepared in the manner indicated the brightly yellow-colored benzoquinone (1,4) diazide (4) 2 (N-4'-methcxyphenyl)-sulfonamide, which, when heated in a capillary tube, decomposes at 165 C.

(18) 1.5 grams of thediazo compound conforming to e rm a.- 8 (q m e Jo l fiir Prak i c Chemie,- volume 24, page 53) are dissolved in cc. of glycol-.monomethyl ether, and this solution is applied by whirlcoating to a roughened aluminum foil. After the layer has been dried and exposed to. light under a negative, there is developed, byv spraying water onto the coated side, a dimly visible positive image, which is wiped over with a one-percent solution of phosphoric acid and then blackened with black printing-ink. A black positive image is obtained that can be used for printing.

It is also possible, however, to effect the development of the exposed layer by wiping it with a five-percent solution of phosphoric acid and by blackening it with printing ink.

If 0.45 percent of aphenol-formaldehyde-resin-novolak, which is supplied by the firm Chemische Werke Albert, Wiesbaden-Biebrich, under the trade-name Alnovol (registeredtrademark in Germany) is; added tothe abovementioned diazo solution, this mixture can be coated. on aluminum plates, and on treatment with a. ten-percent solution of disodium phosphate or with a. three-percent solution of trisodium phosphate,positive images that take greasy printing ink are. also produced from negative masters.

In place of the, abovermentioned diazo compound, the diazo compound conforming to the Formula. 19- can be employed to equal advantage In this. case the image, subsequent to its exposure, is developed with a ten-percent solution of trisodium phosphate.

The 2 -phenyl -ben zoquinone -(1,4) -diazide conforming to. the Fonnula 19 is prepared by the diazotization of 2- phenyl-l-hydroxy-4-arnino-benzene (.Berichte der deuts chen chemischen Gesellschaft, volume 50. (.1917), pages 601402 First the diazonium-chlon'de isformed and the base is set; free. by means. of etherial ammonia. It; remains in theform of a yellow. sirup, when the ether is vaporized.

An equally favorable result is obtained by employing the diazo compound conformingtothe Formula 20. The development of the image is eifected with a fifteen-percent solution of disodium phosphate.

The benzoquinone-(1,4)-diazide-2-phenyl-sulfone conforming to the Formula 20 is. prepared from l-chloro-4- nitro-benzene-Z-sulfochloride (compare Example 1), which is caused to react with benzene, by following the method, developed by Friedel-Crafts, to form l-chloro-4- nitro-2-phenyl-sulfone, which melts at 171 172. C. This reaction product: is melted together with sodium acetate and acetamide and yields. 1-hydroxy-4-nitrobenzene-2- phenyl-sulfone (melting point: C.). The nitro compound is converted, by its reduction with sodium hydrosulfite, into the. amino compound that melts at a temperature of 162'163 C. The diazotization of the amino compound is eiiected in a solution of hydrochloric acid. The diazo compound separates in the form of strawyellow crystals and melts at 154155 C. under decomposition.

( 19) A 1.5-percent solution of the diazo compound;

conforming to the Formula 21 in glycol-monomethylj ether is applied by Whirlcoating to a roughened or anodically oxidized aluminum plate. After being thorough-. ly dried, the layer thus produced is exposed for 2% minutesv under/a transparent negative to lamp at a distance of 70 cm. Then the image is developed with a 0.5-percent solution of caustic soda or with an aqueous solution containing 15-20 percent of tria ethanol-amine. There is obtained a dimly visible positive image which, after being rinsed with water and being wiped over with a one-percent solution of phosphoric acid and greasy ink, yields a strongly colored image that can be used for printing.

In order to accelerate the development of the image, a solutionof two parts of alcohol and one part of; an

an IS-ampere arc 2-carboxylic-acid-anilide,

aqueous solution of calcium chloride of 40 B is used.

The diazo compound conforming to Formula 21 naphthoquinone 1,4) -diazide-(4) -2-sulfone-}8-naphthylamide-is obtained in the following manner: 2.7 grams of naphthoquinone-(l,4)-diazidc-(4)-2-sulfochloride are heated together with 2.8 grams of fl-naphthylamine in 45 cc. of dioxane for twenty minutes at a temperature of 5060 C. and finally for a brief period of time to 70 C. Then, 25 cc. of water are added. On cooling a yellow compound precipitates which is filtered by suction, then washed with water, and recrystallized from acetic ester. Yellow crystals are formed which become brown at a temperature of approximately 140 C. and then slowly decompose.

The naphthoquinone-( 1,4) -diazide-(4) -2-sulfochloride is obtained in the customary manner by causing the potassium salt of l-hydroxy-naphthalene-2-sulfo-acid to react with nitrite and hydrochloric acid and by subsequently reducing the nitroso compound with stannous chloride and hydrochloric acid to form the corresponding 1-amino-4- hydroxy-naphthalene-3-sulfo acid, which precipitates as a white product from the solution and is diazotized subsequent to being filtered, washed with water, and dried.

The diazotization takes place by intensively treating 7.2 grams of l-amino-4-hydroxy-naphthalene-3-sulfo acid with 100 cc. of a seventy-percent solution of alcohol and 5.5 cc. of concentrated hydrochloric acid and adding, while cooling a 2 n-sodium nitrite solution. Subsequent to diazotization, the reaction mixture is reheated, so that the diazo compound, a part of which has already crystallized, is again fully dissolved. Then, the solutionis treated with animal charcoal. The solution is then filtrated and the filtrate is mixed with an equal volume of alcohol. After the solution has been cooled, the crystallized diazo compound is filtered by suction and dried. Finally, it is converted, by heating for an hour together with a fivefold or sixfold quantity of chlorosulfonic acid to a temperature of 9095 C. into naphthoquinone-(1,4)- diazide-(4) -2-sulfochloride, which, after cooling, precipitates as a .yellow product when poured into ice-water. The dried product can be recrystallized from dioxane. It melts at 162 C. under decomposition.

A 1.5-percent solution of the diazo compound conforming to the Formula 22 in pyridine is applied by whirlcoating to a roughened aluminum plate. After being dried, the coated foil is exposed to light under a transparent negative. .The copy thus obtained is developed with an alcoholic calcium-chloride-tri-ethanol-amine developer consisting of a filtrated solution of grams of anhydrous calcium chloride in 95 cc. alcohol 96%, 15 cc. of Water, and 5 cc. of tri-ethanol-amine. The developed image is inked with greasy ink subsequent to being rinsed with water. A positive image is obtained that can be used for printing.

The diazo compound conforming to the Formula 22 is produced, in similar manner to the naphthoquinone-(l,4)- diazide-(4)-2-sulfone-B-naphthyl amide (compare Example 19), by condensing naphthoquinone-(1,4)-diazide-(4)- 2-sulfochloride with 2-amino fiuorene in excess. This yellow diazo compound is very hard to dissolve in the customary solvents. However, it dissolves very readily in pyridine.

(21) A layer, produced with a 1.5-percent solution of the diazo compound conforming to the Formula'23 in monomethyl-glycol ether on a superficially oxidized aluminum plate, is exposed to light under a negative and is developed by means of the same developer as that indicated in Example 20 (diluted, in this case, with an equal amount of water) by being wiped with a cotton swab. Subsequent to its being inked with greasy ink, a positive image is obtained that can be used for printing,

The diazo compound conforming to the Formula 23 is prepared by diazotizing, in alcohol, 4-amino-1-naphthol which can be obtained, for instance, by reducing theazo dye derived from diazotized 16 aniline and 1-naphthol-2-carboxylic-acid-anilide in alcohol with a nickel catalyst and hydrogen under pressure.

The naphthoquinone (1,4) diazide (4) 2 carboxylic-acid-anilide (Formula 23) isa yellowcompound that starts to decompose at a temperature of 128l30 C.

(22) By means of a monomethylglycol ether solution containing 1.5-percent of the diazo compound conforming to the Formula 24 (naphthoquinone (1,4) diazide (4)- 2-sulfo-p-tolyl ester) and 0.75 percent of colophony, there is produced in the customary manner on a roughened aluminum plate a layer, which is dried at a temperature of 90 100 C. and is thenexposed to light under a negative master. The layer is then developed with an approximately Bil-percent solution of alcohol. The positive image thus obtained is inked, subsequent to its being rinsed with water, with greasy ink in the presence of a five-percent solution of phosphoric acid. The inked image can be used for printing in the customary manner.

in order to produce the diazo compound conforming to the Formula 24, 5.4 grams of naphthoquinone-(l,4)-dia zide-(4)-2-sulfochloride and 2.2 grams of p-cresol are introduced into a mixture consisting of 25 cc. of dioxane and 5 cc. of water and gradually 20 cc. of a ten-percent solution of soda are added thereto while heating the reaction mixture slowly to a temperature of 60 C. The naphthoquinone (1,4) diazide (4) 2 sulfochloride, which initially is not completely dissolved, gradually dissolves, and a yellow compound separates towards the end of the reaction. Addition of 150cc. of water to the reaction mixture'leads to the complete separation of the yellow product, which is then filtered by suction and washed with water. After recrystallization from benzene the naphthoquinone (1,4) diazide (4) 2 sulfo p tolyl ester thus obtained melts at approximately 160 C. under decomposition.

(23) A 1.5-percent solution of the diazo compound conforming to the Formula 25 in monomethyl-glycol ether is applied as a thin layer to a superficially oxidized aluminum plate and after drying, the layer is exposed to light under a transparent positive. The exposed layer is developed with a three-percent solution of trisodium phosphate and a positive image is obtained which can be rubbed in V with black greasy ink and used for printing.

If the alcoholic developer mentioned in Example 20 is used in developing the image, it is possible to obtain positive images from negative patterns. 7

The diazo compound conforming to the Formula 25 is obtained by heating, for instance, 2.2 grams of 4,4-diamino-diphenyl-methane together with 5 .4 grams of naphtho-quinone-( 1,4) -diazide-(4) -2-sulfochloride and three grams of anhydrous sodium acetate in 25 cc. of dioxane to a temperature of about 50 C. The temperature 1s finally raised for a brief period of time to 606 5 C., whereby the mixture is darkened. The mixture is then poured into approximately l50-200 cc. of dilute hydrochloric acid and a yellowish-brown product separates which is filtered by suction and washed with water. Recrystallization of the product from aqueous dioxane leads to yellow crystals that do not decompose up to a temperature of 260 C. l

(24) A 1.5-2 percent solution of the diazo compound conforming to the Formula 26 in monomethyl-glycol other is applied as a thin layer in the customary manner to a roughened aluminum plate. The thoroughly dried layer is exposed to light under anegative and developed with an approximately. three-percent solution of phosphor c acid by being wiped over with a cotton swab soaked with the phosphoric acid. The V water and the positive image thus obtained can immediately be used for printing in a printing machine.

In order to produce the diazo compound conforming to the Formula 26 one mole of naphthoquinone (1,4) d1- azide- (4)-2-sulfochloride is condensed with one mole of 7 hydroxy naphtho 2 ethyl N n propyl 1',2':4,5

developed layer is washed with 1 imidazole. This condeiisationis efiected analogously to the method indicated in Exam le 24'.

The yellow diazo compound thus obtained, which is insoluble in water and mines, fails to yield azio dyes on reaction with energetically coupliiig diazo compounds. It must be assumed, therefore, that the condensation has taken place at the hydroxyl group of the 7'-hydroxy naphtho-imidazole. By recrystallization from a mixture ofalcohol and benzene, there are obtained yellowcrystals that start to darken at a temperature of 150 C. and slowly decompose above 200 C. V

The 7 hydroxy naphtho 2 ethyl 'N n -flpropyl 1',2:4,5-imidazole is obtained by heating two moles; of n-p'ropaldehyde with one mole of 1,2-diamino naphthalene-7-sulfo acid in water, until the green iron-chloride coloring has disappeared, and by subsequently melting with alkalies the naphtho 2 ethyl N n propyl l',2:4,5 imidazole-T-sulfo acid thus obtained at atemperature of approximately 240250 C. After recrystallization from aqueous alcohol the 7 hydf6xy=riaphtho-2-ethy1-N- n'-propyl-l',-2': 4,5-"imidazole melts at ZS li C. M I

A one-percent solution of naphthoqumone-(alg iydiazide(-4-)-2 sulfone ,3-naphthylamide (Formula n monomethyl-glycol ether is applied bymeans of a platewhirler at a speed of 100 revolutions per minuteto: a casein coated paper foil which is obtainable by the method indicated in the British Patent 633,796. The'iayr is dried by means of hot-air. Then, it is exposed to light under a transparent negative and developed a developer that is produced from 50 gramsof calcium chloride, 70 cc. of ethyl alcohol (96%) and" cc. water. After the layer has been rinsed with water, the positive image obtained is wiped over with an aqueous solution containing 50% of glycerine and 2.5% of an acid phosphate and is then inked with greasy black printing ink, and used for printing in the customary manner.

(26) An aluminum foil having a roughened surface is coated with a thin layer by applying to the foil a solution containing per 100 cc. of pyridine 1.5 g. of naphthoquinone-( 1,4) -diazide-(4) -2-sulfone-benzyl-amide (Formula 27) and drying. The dry light-sensitive layer is exposed to actinic light behind a negative master and after exposure the layer is developed by treating it with a 60-percent alcohol solution or 5-percent phosphoric acid. A positive weakly yellow diazo image becomes visible which is greasy ink receptive and may be used for making copies of the image by means of a printing machine.

The diazo compound of Formula 27 is prepared as follows: 2.7 g. of naphthoquinone-(1,4)-diazide-(4)-2- sulfochloride (compare Example 19) are dissolved in 70 cc. of dioxane while heating and at a temperature of 45 50 C. 2 g. of benzylamine are added to the dioxane solution. Benzylamine hydrochloride will separate out. The solution is heated to approximately 50 C. for a short time, then cooled to room temperature, and mixed with 150 cc. of water. A solid body separates out which is filtered off by suction, washed with water and dried. This body is naphthoquinone-(1,4)-diazide-(4)- Z-sulfone-benzylamide which forms light-yellow crystals after recrystallization from a mixture of dioxane with water. On heating, the crystals decompose at approximately 165 C.

(27) A 1.5% solution of naphthoquinone-( 1,4)- diazide-(4)-2-sulfone-N-n-butylamide with the Formula 28 in monomethyl-glycol ether is coated, as described in Example 26 onto an aluminum foil mechanically roughened with the aid of a brush and is dried. In the same manner a positive image suitable for printing is obtained by exposure of the formed fight-sensitive layer under a negative and subsequent development.

Instead of the aluminum foil a paper foil, produced as described in U. S. Patent No. 2,534,588, can be sensitized with the solution described above, and a paper- T8 printing foil can be pre -area therefrom in the same manner.

In similar manner to the analogously constituted benzylamide (Example 26'), the naphthoqirinone-(IA)-diazide- (4)-2-sulfone N-n=butylaifiide is prepared by reaction of 2 molecules of n-butylamine on 1 mole of naphthoquinone-(1,4)-diazide-(4) 2-sulfochloride (Example 19) in dioxane. After recrystallization from benzene it represents a feeble yellow-colored crystal-powder which decomposes-at 156 C.

(28 A. 1% to 1.5% solution of the condensation product of naphtho'q'uinone-(IA) -diazide-( 4) -2-sulfochl'o-' ride and 2-methyl-benziniidazole (Formula 29.) in monomethyl-gly'c'ol ether is applied onto a roughened aluminum foil in the usual manner. The thus formed, well dried layer is exposed to light under. a negative. After development with a- 5% .solution of phosphoric acid, to which a 10% solution of monomethyl-glycol ether may eventually be added, a positive image is obtained that can be used. tor printing in the usual manner.

The diazo compound with the Formula 29 is produced in the following manner: a warm solution of 2.7 g. of naphthoquinone-( 1,4)-diazide-(4)-2 sulfochloride (Example 19') isladde'd to a solution of mixture is heatedto 45 50 the reaction fnass ayellow cipitates upon-cooling. The separation can be completed by addin'g a solution or dilute hydrochloric acid. The condensation product is filtered by suction and washed with water. After reefyseinzauan fro a mixture of :23 3 parts of "(hexane and 1 part of alcohol, a yellow crystalline product is obtainedwhich starts decomposing at about 270 C. I It is diflicultly soluble in alcohol and more easily soluble in dioxane or monomethyl-glycol ether.

Having thus described the invention, what is-(Slaimed is:

1. An article for use in the manufacture of printing plates comprisinga base and a light-sensitive layer coated on saidbse adapted to beingconverted into imagedand non-imaged areas, said light-sensitive layer including at least one water insoluble para-quinone-diazide of the group consisting of aryl substituted sulfonamides, aryl substituted sulfo acid esters, aryl substituted carboxylic acid amides of para-benzoand para-naphthoquinone diazides, and aryl substituted carboxylic acid esters of para-benzoquinone diazides.

2. An article according to claim 1 wherein the water insoluble para-quinone-diazide is an aryl substituted sulfonamide of para-benzoquinone-diazide.

3. An article for use in the manufacture of printing plates comprising a base and a light-sensitive layer coated on said base adapted to being converted into imaged and non-imaged areas, said light-sensitive layer including the water insoluble compound of the formula SOr-NH- 4. An article according to claim 1 wherein the water insoluble para-quinone-diazide is an aryl substituted sulfonamide of para-naphthoquinone diazide.

5. An article for use in the manufacture of printing plates comprising a base and a light-sensitive layer coated on said base adapted to being converted into imaged and 2.6 g. of 2-niethylbenzimidazolein 40 cc. of dioxaiie, and the reaction- C'. for 15 minutes. From condensation product pie- '19 non-imaged areas, said light-sensitive layer including the water insoluble compound of the formula non-imaged areas, said light-sensitive layer including the water insoluble compound of the formula 8. An article according to claim 1 wherein the water insoluble para-quinone-diazide is an aryl substituted sulfo acid ester of para-naphtho-quinone diazide.

9. An article for use in the manufacture of printing plates comprising a base and a light-sensitive layer coated on said base adapted to being converted into imaged and non-imaged areas, said light-sensitive layer including the water insoluble compound of the formula 10. The article of claim 1 wherein said layer includes an alkali-soluble phenol-formaldehyde resin.

References Cited in the file of this patent UNITED STATES PATENTS 548,460 Ris Oct. 22, 1895, 1,160,362 Baekeland Nov. 16, 1915; 2,179,239 Wilmanns et a1 Nov. 7, 1 939 2,407,376 Maxwell Sept. 10, 1946 FOREIGN PATENTS 747,246 France Mar. 28, 1933 785,041 France- May 13, 1935 890,976 France Nov. 19, 1943' 904,255- France Feb. 19, 1945 997,596 France a Sept. 12, 1951 22,297 Great Britain 1900 539,314 Great Britain Sept. 4, 1941 618,181 Great Britain Feb. 19, 1949 473,217 Germany Mar. 14,1929

470,026 Canada Dec. 12, 1950 OTHER REFERENCES 

1. AN ARTICLE FOR USE IN THE MANUFACTURE OF PRINTING PLATES COMPRISING AN BASE AND A LIGHT-SENSITIVE LAYER COATED ON SAID BASE ADAPTED TO BEING CONVERTED INTO IMAGED AND NON-IMAGED AREAS, AND LIGHT-SENSITIVE LAYER INCLUDING AT LEAST ONE WATER INSOLUBLE PARA-QUINONE-DIAZIDE OF THE GROUP CONSISTING OF ARYL SUBSTITUTED SULFONAMIDES, ARYL SUBSTITUTED SULFO ACID ESTERS, ARYL SUBSTITUTED CARBOXYLIC ACID AMIDES OF PARA-BENZO- AND PARA-NAPHTHOQUINONE DIAZIDES, AND ARYL SUBSTITUTED CARBOXYLIC ACID ESTERS OF PARA-BENZOQUMONE DIAZIDES. 